1. Field of the Invention
This invention relates to a hand-pushed carrier trolley which is intended to be employed for transporting merchandize, in particular in wholesale self-service stores as well as in warehouses of retail stores.
2. Description of the Prior Art
Hand-pushed carrier trolleys are used under widely varying service conditions and there are consequently many different types of trolleys in existence.
One type of carrier trolley in general use is the trolley employed in commercial stores and having four wheels which are all free to swivel about a vertical axis. The advantage of these carrier trolleys is that their frames can be so designed as to fit one inside the other in order to group the trolleys together in a small volume when they are not in use. To this end, instead of being carried by a bottom platform, the trolley wheels are secured to the four corners of a horizontal peripheral member having the shape of a trapezoid, the large base of which is located at the rear end and completely open in order to permit engagement of another identical trolley. However, these trolleys are subject to a disadvantage in that they are difficult to steer since they have a tendency to run in an undesired direction. This tendency is aggravated as the load on the trolley becomes greater. Attempts have been made to overcome this disadvantage in the case of four-wheeled trolleys by giving freedom of pivotal motion only to the rear pair of wheels. However, trolleys designed on this principle have a long turning radius and are consequently not readily maneuverable.
There also exists another type of trolley in which it is sought to achieve greater maneuverability by means of a pair of non-swiveling central wheels in addition to two pairs of swiveling wheels located respectively at the front and rear ends, these central wheels being placed at a lower level than the front and rear wheels. These trolleys are particularly easy to maneuver since they pivot on the central pair of wheels and can readily be directed even if they are heavily loaded. The defect of these carrier trolleys, however, lies in the fact that they do not engage one inside the other and consequently entail the need for considerable storage space. In order to permit the presence of central wheels, it is in fact necessary to provide trolleys of this type with a bottom platform beneath which these central wheels are fixed. This accordingly excludes any possibility of interengagement of trolleys of this type.